Keel boat



United States Patent Charles Elie-Louis Chauveau 21, rue de General Margueritte, Nantes, France Aug. 23, 1968 Dec. 15, 1970 lnventor Appl. No. Filed Patented KEEL BOAT 4 Claims, 8 Drawing Figs.

US. Cl 114/138, 114/141 Int. Cl B6311 41/00 Field of Search [56] References Cited UNITED STATES PATENTS 465,114 12/1891 Paul 114/141X 667,158 1/1901 Webster 114/138 Primary Examiner-Trygve M. Blix AttorneysAnthony William Drucker and Peter L. Trailer and Jay Cantor ABSTRACT: In a boat with a movable drop keel in a dropkeel well, the said drop keel is ballasted at the bottom and operating equipment is provided to immerse the drop keel and to raise it in order to bring the ballast in contact with the hull of the boat, a rigid guiding structure for the drop keel being detachably mounted in the drop-keel well and comprising upper and lower U-shaped iron sections respectively in contact with the two upper and lower side walls of the drop-keel well.

PATENTED DEC] 5 I970 SHEET 1 [1F 3 KEEL BOAT This invention relates to bulb-keel boats, i.e. boats with a drop keel ballasted at the lower end.

These boats, which are of larger tonnage than drifters, have the disadvantage of having a considerably draught, which limits their use and makes it impossible for them to gain access to many coastal ports. If they run aground, it is comparatively difficult to refloat them.

Drifters overcome this disadvantage by means of a movable metal plate termed a drop keel, which is immersed as required under the keel proper (the latter forming part of the timbers of the vessel) and which can be raised into a watertight opening, called a drop keel well" in the boat. This solution is generally applied to small sailing vessels.

The equipping of certain drifters with a weight fixed under the keel, around the opening of the drop keel well, has already been thought of. When the drop keel is immersed, this fixed weight does not provide fully satisfactory stability for a vessel of comparatively high tonnage. This solution, moreover, is not very satisfactory from a hydrodynamic point of view, as the weight, permanently situated under the keel proper, causes eddies to form.

This invention covers a boat with a movable drop keel in a drop keel well, featuring the fact that the aforesaid drop keel is ballasted at the bottom, which ballast comes under the keel proper when the drop keel is raised while, when the drop keel is immersed, it ensures that the vessel is perfectly stable without detriment to the hydrodynamics.

An important peculiarity of the invention is that the aforesaid drop keel, drop keel is ballasted at the end of the lower, immersible part, works in conjunction with a rigid guiding structure fixed detachably in the drop keel well, which structure supports two units of rotating parts on which the two edges of the aforesaid drop keel run, means being provided to effect this running in order to raise and immerse the aforesaid lower part.

In one method of construction designed in particular for boats of comparatively small tonnage, the aforesaid drop keel is in the form of a curved board with cut outs in the nonimmersible part. Other features, as well as the advantages of the invention, will emerge clearly from the following description.

In the attached drawing:

FIG. 1 is a diagrammatic, longitudinal section view of the forward part of a vessel fitted with a curved drop keel in accordance with the invention;

FIG. 2 is a drawing'of the sole piece which closes the guiding sleeve of the drop keel in FIG. 1;

FIG. 3 shows the profile of this drop keel and its guiding structure;

FIG. 4 is a diagrammatic, longitudinal section view of the center part of the keel of a vessel fitted with a drop keel in accordance with a constructional variation;

FIG. 5 is a drawing of the sole piece which closes the guiding sleeve of the drop keel in FIG. 4;

FIG. 6 is a section from A to B in FIG. 4;

FIG. 7 shows a profile view of the aforesaid drop keel and its guiding structure;

FIG. 8 shows a detail of the mounting of the pulleys included in the system for raising the drop keel shown in FIGS. 4-7-8.

FIGS. 1 and 3 show the forward part of the keel proper I of a vessel, which part includes the stem 1a. In the center part of the keel there is the opening of a drop keel well, closed by a sole piece 2 slotted at 2a, a detail of which is shown in FIG. 2; this sole piece 2 is fixed to the keel by means of bolts such as 3. The timbers of the vessel include a drop keel well the sidewalls of which can be seen at 4 and 5 in FIG. 3.

An important peculiarity of the invention is that the drop keel 6, ballasted at its bottom end 6a, is mounted movably in a detachable metal sleeve manufactured separately and fitted with sheaves, the whole then being inserted into the drop keel well and fixed as will now be explained.

This sleeve is a rigid metal framework made up of two U- shaped iron sections (7 and 8, FIGS. 1 and 3) joined by three pairs of crosspieces 9-94 (FIG. 3), 10-100, 11-11a (FIG. 1) forming connecting webs between the vertical U-shaped arms.

' As may be seen in FIG. 3, the iron section 7 is connected to the upper part of the timbers of the boat by a support 7a-7b bolted on either side of the sheave 16. The rigidity of the guiding structure of the drop keel is thus increased, which enables it to stand the torque to which it is subjected, without excessive lateral flexion.

The sleeve just described is completed by a sole piece 2, welded to the base of the iron sections 7 and 8. The latter bear a certain number of sheaves (12 to 22, FIG. 1; in FIG. 2, only the upper sheave 16 has been shown) the axles of which pivot in the vertical arms of the iron sections. The mounting of these sheaves will be described more fully below.

Once the sleeve, fitted with its sheaves, has been inserted into the drop keel well, the sole piece 2 is fixed to the keel as explained above.

It would have been possible to mount the sheaves directly in the walls of the drop keel well. In practice, this solution is not satisfactory. In fact, the piercing of the aforesaid walls in order to admit the axles of the sheaves is difficult to achieve with a greater precision than half a centimetre. In any case, strain on the wood quickly alters the dimensions. Now, if the sheaves are too close together, the drop keel gets jammed when it moves, while if they are too far apart, some play occurs, which causes vibrations and even the derailment of the drop keel.

An important peculiarity of the invention is that all drilling of the timbers has thus been eliminated, the sheaves being mounted, as has just been described, in a rigid sleeve, manufactured separately in a workshop. The mounting, which is very' precise, may be checked periodically since the unit is detachable. The mounting cannot be deformed and, by reason of the degree of precision achieved, a comparatively large number of sheaves can be provided, which makes for smooth, vibration-free running.

The system for raising the drop keel with which the vessel is fitted will now be described. -A cable 23, moved by a winch 24, preferably with a catch and forming a brake, is fixed to the stem at 25 and passes over pulleys 26 (fixed to the end of the drop keel) and 27 (fixed to the stern).

The drop keel has been shown in the immersed position. Operating the winch raises it into the position partly shown by dotted lines; the bulb 6a then comes to rest directly on the bottom of the hull, so that the draught is greatly reduced. To immerse the keel, it is sufficient to release the catch. The drop keel then slides on the sheaves which guide its descent, until the stop 28 comes up against the sheave 16.

It can be seen in FIG. 1 that rubber shock absorbers 29 have their ends fixed respectively at 30 to the stem and at 31 to the upper end of the drop keel. These rubber shock absorbers contribute to braking the descent of the keel and facilitate its raising, as they then exercise a gradually decreasing pull.

The upper sheave 16 can be dismounted; this makes it possible to free the stop 28 and remove the drop keel without dismounting the sleeve.

In the method of construction shown in FIGS. 1 and 3, the drop keel is in the form of a curved board, which reduces the height of the drop keel well. This solution is particularly useful for vessels of comparatively small tonnage, as it reduces the bulk in the center part of the boat; the drop keel can, for example, end up between two bunks, in the forward part.

Cutouts 32-33 lighten this curved keel. The iron sections of the sleeve and the drop keel well are, of course, curved correspondingly.

For larger vessels, it is better to use a straight drop keel, penetrating into a well which is slightly sloping in relation to the vertical. This solution corresponds to the method of construction shown in FIGS. 4 and 7 and obviates any substantial displacement of the vessel's center of gravity by the operation of the drop keel.

In FIGS. 4 and 7 it can be seen that the drop keel 34, fitted with a bulb 34a, is guided in a sleeve mounted in the drop keel well of the vessel. The sidewalls of the drop keel well are shown at 35-36. The sleeve comprises two U-shaped iron sections, 37-38, connected by crosspieces 39 drop keel 41. Sheaves 42 to 53 are mounted in the vertical walls of these two iron sections. A sole drop keel 54, shown in detail in FIG. and fitted with an opening 54a to allow the drop keel to pass,

is welded to the base of the drop keel iron sections and fixed to the timbers 55 of the vessel, by means of bolts such as 56.

The method of mounting and guiding the drop keel is thus essentially the same as in the method of construction in FIGS. 1 and 3.

The section in FIG. 6 shows that the drop keel well is closed laterally by two crosspieces 57 and 58 positioned between the walls 35 and 36.

The raising system with which the vessel is equipped includes a double-wind winch 59, a first cable 60 which goes over a double-groove pulley 61 and a single pulley 62 and is fixed at 63 to the end of the drop keel, and a second cable 64 which goes over the pulley 61 and over asingle pulley 65 and is fixed at 66 to the end of the drop keel.

These pulleys are mounted on an iron section 67 fixed to the timbers of the vessel as can be seen more clearly in FIG. 8. The ends of the iron sections 37 and 38 are bolted to the faces of this iron section 67.

The raised position of the drop keel has been shown in dotted lines on FIG. 4.

To avoid losing the drop keel should the raising cables accidentally break, two flat pieces of iron have been provided, one of which, 68, can be seen in FIG. 4. These flat pieces of 'iron, bolted to the keel, butt against the sole piece 54 when the keel is lowered.

Needless to say, various modifications could be made to the methods of construction described and shown, without departing from the spirit of the invention.

Iclaim:

1. Boat with a movable drop keel in a drop keel well, said drop keel comprising a bulb at the bottom, operating equip ment being provided to immerse the drop keel and to raise it inorder to bring the bulb in contact with the hull of the boat, a rigid guiding structure being detachably mounted in the drop keel well, the said guiding structure supporting two units of guiding means on which the two edges of the drop keel run, the aforesaid guiding structure comprising an upper U-shaped iron section and a lower U-shaped iron section, respectively in contact with the two upper and lower sidewalls of the drop keel well, several crosspieces forming connecting webs between the corresponding vertical arms of the U-shaped iron sections, a sole piece fixed to the base of the aforesaid U- shaped iron sections and fitted with an opening to allow the drop keel to pass, and means of fixing the aforesaid sole piece detachably to the hull of the boat, the aforesaid guiding means consisting of rotating units mounted so as to pivot between the aforesaid vertical arms.

2. Boat as in claim 1, in which the aforesaid guiding structure comprises in addition a support which connects the upper end of the aforesaid upper U-shaped iron section to the upper part of the hull.

3. Boat as in claim 1, in which the aforesaid rotating units are made up of sheaves and include a sheave mounted detachably on the upper end of the aforesaid upper U-shaped iron section and in which the aforesaid drop keel comprises a stop which works in conjunction with the aforesaid detachably mounted sheave.

4. Boat as in claim 3, in which the aforesaid operating units include a winch, a cable operated by the aforesaid winch, at least one pulley fixed to the hull and over which the aforesaid cable passes, and at least one rubber shock absorber with one end fixed to the hull and the other end fixed to the aforesaid stop. 

